Effect of sulfur sources on the crystal structure, morphology and luminescence of CdS nanocrystals prepared by a solvothermal method

CdS nanostructured materials were prepared by a chemical synthesis via the reaction of Cd(NO3)2.4H2O and various sulfur sources. The products were characterized by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM). The results indicated that the samples prepared with Na2S.9H2O were zinc blende crystal structure in sphere-like shape and the products prepared with thiourea and sulfur were both wurtzite crystal structures in rod-like shape. The room-temperature luminescence revealed that all the CdS nanostructured materials had a broad green emission band and a red emission band. In addition, the growth mechanisms of the CdS nanocrystals were preliminarily discussed.